In an existing manufacturing procedure of a thin film transistor liquid crystal display screen (TFT-LCD), an alignment film (PI film) is coated on both sides of a thin film transistor substrate and a color film substrate (TFT/CF) in order to allow liquid crystal molecules to have a fixed pretilt angle.
There are mainly two approaches to coat the alignment film on a glass substrate: inkjet and print, wherein a printing plate (APR plate) is usually necessary for print.
The printing plate is made of a resin material. As shown in FIG. 1, with the increase in the number of prints, the resin material will be stretched, leading to deformation of a pattern on the printing plate. An arrow in FIG. 1 indicates a stretching direction. As a result, as the number of prints increases, an operator will observe deformation of the pattern on the printing plate, and move a printing roller integrally to enable integral correction of the pattern on the printing plate. Due to different stretching degrees, a printing start end and a printing end will be different from each other in deviation values of the pattern, as shown in FIGS. 2 to 4, which depict in a direction from the printing start end to the printing end. Different positions have different stretching degrees. However, integral correction causes integral deviation, and thus cannot meet different correction requirements of different printing positions due to the different stretching degrees. Therefore, even if an image on the printing plate is corrected through integral deviation, the pattern of the alignment film at different positions of the printing plate is still subject to different degrees of deviation. Solid lines in FIGS. 1 to 4 indicate original boundaries of the pattern, and dashed lines therein demonstrate boundaries of the pattern after being stretched.
In order to solve the problems in the prior art, it is necessary to provide a new correction system and method for the alignment film printing plate.